One of the problems that has arisen in connection with vacuum ovens or furnaces is that of heat distribution in the oven. That is, all of the work area doesn't see a similar radiation field. Inconsistent and irregular radiation fields can result in hard spots or residual stress in metals, different surface finishes and color variations in ceramics and porcelains, and a myriad of other issues in more exotic materials. These inconsistent and irregular radiation fields necessitate new vacuum ovens that have more uniform radiation fields.